Not Enough
by Killerchainsaw
Summary: After finding out about a weird little fetish of Illya's by accident, Kuro becomes more interested in the subject, and decides to have a little fun with her sister, only to realize a little too late that enticing Illya, and flipping her switch may be more dangerous than she had first thought. Just another Illya x Kuro fic, with lots of sister-shipping for you all to enjoy.


**Author's Notes:**

 **I don't own Fate/Kaleid Liner Prisma Illya or any of its character's, no copyright is intended.**

 _Italics - Means the person is thinking just so you know._

 **Warning: This contains yuri (girl x girl) pairings, as well as incest, don't like? Don't read simple, otherwise enjoy. ;) **

**Warning: This contains lemon ;P**

 **...**

On this warm summers day off from school Kuro lay on her sister's bed, staring up at the ceiling as she was meant to be doing her homework right now, but instead was just slacking off as she sighed deeply, draping an arm over her eyes while she felt like just going to sleep.

Although she knew she should get on to studying she honestly just had no motivation at the moment, plus it wasn't like she was able to concentrate when all she could think about was how much she didn't want to bother with the piles of summer homework she was meant to get done before school started back up in a couple of weeks.

After spending most of the day out in the sunshine with her friends, Kuro just didn't feel like sitting down to write for however long it would take until dinner was ready, so that she could stop and go eat with everyone else, knowing that Sella wouldn't let her leave Illya's room until she got at least some of her homework done. She had wanted to stay in her own room which she shared with their Mother, but at the moment it was apparently 'being cleaned' and she wouldn't be able to go in there until tonight.

Kuro knew that was just a lie to keep her out of the bedroom as much as possible so that it would be tidy for when Irisviel was due back from her trip, since Kuro had never been one for cleaning up after herself and keeping things organized.

So now she was locked in her sister's room, pulling herself up off the bed and looking down to all her homework sheets, gritting her teeth tightly before she kicked and sent the papers flying around the room, watching them all fall to the floor. Running a hand through her long pink hair slowly, letting herself fall back onto her sister's bed and giving out another heavy sigh.

"Oh Kuro, you're meant to be writing down on those papers of homework not throwing them around like that," Ruby stated as she jumped up from where she had been resting on her master's bedside table, the sound of Kuro kicking her homework around the room catching her attention as she now flew over to the young girl and hovered above her.

"How can I when I can't focus on anything right now? It's too hot to be keeping me locked in a room like this and making me do nothing but study," Kuro explained as she rolled over onto her stomach, and looked to the magical wand with a bored stare.

"Oh, well if it's motivation you're having trouble with, I know the perfect way to get your mind back on track," Ruby exclaimed proudly, thinking that she could have some fun now since she had been made to stay in the room all day while her master had been out with her friends, and hadn't brought her along with her.

"What's that?" Kuro asked seeming uninterested as she propped herself up on her elbow, and raised an eyebrow to the wand, wondering if she really wanted to know what Ruby was planning right now.

"Well its simple, all you need to do is make some clothes using your mana,"

"How will making clothes help motivate me more?" Kuro questioned, feeling like she was going to regret asking once she had heard Ruby's answer.

"Because the clothes that you will create will no doubt boost your confidence, and motivate you to get as much of your work done before your dinner is ready," Ruby spun around happily, her voice sounding excited as she knew Kuro was too tired to bother to continue to ask her any more questions, plus since she wasn't allowed to leave Illya's bedroom until most of her homework was done, the young girl's only option would to go along with Ruby's suggestion.

And just as Ruby had thought, Kuro agreed to her idea sighing slightly as she nodded her head, and soon stood up from the bed again, letting herself be roped into the magical wand's 'little game'.

…...

Meanwhile Illya was downstairs helping Sella and Shirou with cooking dinner, happily helping to prepare the meal for everyone, while Liz lay stretched out on the lounge sofa watching the television, and waiting for the food to be ready.

Illya was mostly just watching her big brother cook instead of actually giving him much of a hand, as she stood smiling upto Shirou, him smiling back down to her for a moment, before he carried on with cooking and Sella called over to Illya, dragging her attention away from her older brother for a moment.

"Illya dinner should be ready soon, so can you go and tell Kuro that she better have gotten a good amount of her homework done, or she'll be staying in your room for even longer," Sella instructed to the young girl, Illya simply just nodding and smiling in reply, before she took off her apron and ran off to go and get her sister, making her way up the stairs and across the hallway to her bedroom.

Unlocking the door quickly as she wanted to get back downstairs so she could continue to 'help' her brother with making dinner before it would be all ready to serve to everyone. Knocking on the door lightly, as she opened it slowly looking around for her sister, while walking into the room and closing the door behind her.

"Kuro, dinner's almost ready, so Sella wanted me to come and see how much work you've gotten done," Illya stated, before she stopped dead in her tracks and stared wide eyed at the sight that was now right in front of her.

There before her stood Kuro, who had been somehow transformed into a maid all of a sudden, a maid with perky little black cat ears that sat twitching on top of her head, and a long black tail that curled back on itself at the very end, the smooth and furry appendage swishing along with the young girl's body whenever she moved.

"Oh hey Illya, is dinner ready yet?" Kuro asked only just now noticing that her sister had entered the room, as she turned to look to her while she wore what looked like quite an annoyed expression on her face.

"W-w-what are you wearing?"

Illya stuttered as her body trembled, feeling her heart starting to race in her chest, and heat beginning to raise up into her cheeks, her breathing instantly becoming heavy, as she held herself against the wooden door and suddenly felt a strong desire building up inside her from deep down in her core.

"Oh this? Ask your dumb wand," Kuro stated as she looked down at the maid outfit she was wearing, feeling foolish for agreeing to create and wear such a weird costume for the wand.

"Illya I'm glad you're here, this outfit is just one of many that I have planned for Kuro to create, and I'm sure you wouldn't mind trying them on as well," Ruby explained happily as she floated over to her master, while Kuro just rolled her eyes in an annoyed way.

"I still don't get how these clothes are meant to motivate me to study, they just look ridiculous,"

"Far from it Kuro, they look just adorable on you, and I already told you these clothes are specifically created to help boost your confidence and self-esteem, and thus helping you in your lack of motivation. Believe me they will be sure to make you become more focused the longer you wear them," Ruby explained excitedly as she flew back over to Kuro, and couldn't wait to have the young girl create more clothes and try them on.

"I highly doubt that that's what they do, since I don't feel anything close to being focused right now," Kuro mumbled underneath her breath, sighing heavily before she looked back to Illya and noticed that she looked a little off, not to mention that she was also shaking a little right now.

"Are you okay Illya?"

Kuro asked looking over to her sister with a wondering expression, tilting her head to the side a little while the cat ears resting on top of her head moved by themselves it seemed, twitching and flicking back as they followed where Kuro's head went.

Illya freezing for a moment, as she watched Kuro's little ears twitch, and fall back onto her head at one point, her slightly swishing tail catching Illya's ruby red eyes, as she seemed mesmerized by the way it moved along with Kuro's body as she came walking forward a little. Taking a couple of steps towards her sister, her eyes moving up the other girl's body, scanning over the cute maid outfit before stopping at her face, and coming out of her trance when she saw that questioning look that the dark skinned girl was giving her right now.

"Oh yes, I'm fine, umm…Kuro could you close your eyes for a moment please?" Illya asked with a smile now, as she slowly walked upto Kuro. Kuro just becoming more confused as she stepped back slightly now, while looking to Illya was a puzzled and uneasy expression.

"Close my eyes, what for?" Kuro asked, taking another step back as Illya was now awfully close to her all of a sudden.

"Well I guess it doesn't matter all that much if your eyes are open for this," Illya stated, her tone sounding slightly off from her normal way of speaking, as she smiled to her sister coming closer to her, and causing her to back up until her back hit the wall behind her.

"Illya what are you talking about?" Kuro questioned, raising her voice a little as she wondered what her sister was going on about, while also questioning to herself why she had backed her up against the wall like this.

"Kuro…" Illya paused, as she took a deep breath and let her desires run wild, grabbing hold of both of Kuro's hands and pinning her up against the wall roughly, before she leaned in and licked her lips with a smirk, "…you look really cute in this outfit," she finished before she pressed her lips to her sister's and kissed her deeply.

Kuro's eyes going wide as she stood frozen for a moment, coming back to her senses when she felt Illya's hot tongue slip into her mouth, not even bothering to ask for an entrance as she deepened the kiss and started to explore every inch of her sister's mouth, sucking on her tongue a few moments later.

"Illya…what are you…Illya…stop…"

Kuro struggled between kisses as she squirmed against her sister trying to get free, while gasping for air as Illya kissed her over and over again, saliva soon coating and running down their chins as Illya suckled on Kuro's tongue softly, causing her sister to moan in return as she panted heavily and felt her eyes filling with tears now.

Illya wasn't listening, as her mind was blank, and right now she was allowing her desires to get the better of her biting down on Kuro's bottom lip, and seeing just how far she could reach her tongue down the back of her sister's throat. Kuro chocking back moans as she felt like biting Illya's tongue in order to make her stop.

"Illya…stop…Illya…"

Kuro panted out heavily between breath-taking kisses, feeling her heart beating fast and her lungs begging for air, shivering all over when she suddenly felt Illya let go of one of her hands, and grab hold of her tail instead.

Gently cradling the furry appendage in her hand, as she stroked the very tip of it lightly, combing her fingers through the dark fur, and letting the end curl around her hand. Kuro trembling a little as she couldn't feel anything through her fake tail, however it was still slightly off putting to see her sister play around with her 'tail', like it was actually her's, and not just something made with her mana.

By now Kuro had had just about enough, feeling so out of breath as Illya didn't let her catch a single gasp between their kisses anymore, and she had put up with this for long enough now, breaking their rough kiss, and pushing both of her hands against Illya's chest, holding her away from her, and stopping her from getting any closer in case she tried to kiss her again.

"Illya stop! Just what has gotten into you all of a sudden?" Kuro asked getting her breath back now, as she still panted a little, looking to Illya with a questioning expression, which also seemed to be a look of worry.

Illya was still letting her desires speak for her it seemed as she just stood gazing to Kuro, seeing her sister's slightly blushing face, while Kuro stood there holding her back to stop her, still panting heavily, and Illya now noticing that her eyes were filled with slight tears, _'Is Kuro…scared of me right now?'_ she questioned, before she shook her head and snapped herself out of her trance-like state, coming back to her senses, as she quickly let go of Kuro's fake tail and backed away from her now.

"I umm…" Illya didn't know what to say, not able to look Kuro in the eye anymore, as she looked down at the floor, blushing deeply as she opened her mouth again, "D-dinner is almost ready now, so Sella wanted me to come up and tell you to come downstairs," she stated in a rushed voice, feeling her heart pounding in her chest, turning on her heel a moment later and quickly leaving the room, slamming the door behind her loudly, as she quickly ran down the stairs and away from her sister.

Kuro still stood against the wall, breathing a little calmer now as she sighed deeply, looking up to Ruby, "What the hell was that about?" she asked, while Ruby just shrugged to her in reply, also seeming awfully surprised by the way her master had acted towards her sister, neither one of them knowing just what had come over Illya so quickly.

….

After a dinner where she and Illya didn't speak a single word to each other, Kuro now sat on the sofa in the lounge, looking at the television but not really paying any attention to the program that she and Liz were watching, as she was more or less just staring off into space, while being lost in thought it seemed.

' _Just what had gotten into Illya back then I wonder, she's never the one to normally kiss me, and whenever we do kiss for mana…she's never been that rough with me. But her touch was so gentle at the same time, the way she held both of my hands, and the way she played with my 'tail'…although I couldn't feel anything through it, it almost seemed as if she was expecting me to give her a reaction at the time, and I guess I did by shivering, but that was because she was acting so out of character towards me. Plus she had such a smug expression on her face, almost seductive, I've never seen her act like that towards anyone before,'_ Kuro went over everything that had happened a couple of hours ago, and tried to figure out just why her sister had done all those things to her.

Thinking back Kuro wondered just what had caused Illya to act so unlike herself, being unsure of herself for a few moments, before her eyes widened a little in realization, _'Wait…she seemed a little off when she walked into the room and saw me wearing that stupid cat-maid outfit that Ruby had me make. She started acting weird, she played with my 'tail' and held me up against the wall, and there's also the thing she said to me before she started to kiss me, '…you look really cute in this outfit,' just what did she mean by that?'_

Kuro then sighed as she turned to look over to where her sister was, seeing her helping to wash the plates with what looked like an uninterested expression on her face, _'Normally she would be overjoyed to wash the dishes with Onii-chan, but not right now it seems,_ ' she thought, before going back to looking at the television screen again.

' _Maybe she has a 'cute fetish' of some sort… she seemed like a completely different person. Could I have flipped a switch from wearing that outfit in front of her?'_ Kuro wondered, glancing back to her sister once again, but looking back to the T.V when Illya didn't look back to her, and just kept her gaze focused on the plates she was washing, looking like she hadn't noticed Kuro staring at her when really she had.

Feeling Kuro's preying eyes on her, Illya kept her eyes cast down, not wanting to make eye contact with her sister after what she had done to her not too long ago, after not being able to look, or talk to her throughout the whole of the afternoon, now only lifting her head up and glancing back to her sister when she knew she had turned away from her.

' _Why did I do something like that to Kuro? I couldn't talk or even look at her through dinner, she no doubt probably wants to know why I kissed her like that so suddenly. I know I've always taken a liking to cute things but…never like that before. I think I need to keep my own desires in check better…but that maid outfit, and those little cat ears, not to mention that curled tail she was wearing it…she just looked so cute like that I couldn't help myself. No wait stop that! She's your sister, I shouldn't go including her in my weird fantasies,'_ Illya thought to herself with a heavy sigh, trying to stay focused on finishing getting all the dishes clean, rather than thinking about the way she had acted towards her sister a little while ago, remembering something as she sighed a little now,

' _She looked so…frighten of me at that point, I'm an idiot,'_ she cursed herself under her breath as it seemed like the memory of Kuro's scared face wasn't going to be leaving her mind anytime soon unfortunately.

' _Although that was awfully surprising to see from Illya, it also was quite interesting, and she seemed to know what she was doing when kissing and playing with me. I wonder could I make her act like that towards me again?'_ Kuro now questioned as she was looking over at Illya again, a small smirk making its way onto her lips, as she now stood up from the sofa and headed towards the staircase, _'This could actually be fun to try out,'_ she thought to herself, before leaving up the stairs.

Illya lifted her head again as she heard slight footsteps from the lounge, and saw Kuro leaving to go upstairs now, guessing that she was most probably going back upstairs to finish her homework. Illya was going to just turn back to what she was in the middle of doing, but instead she thought of maybe following Kuro and apologizing to her for what she did to her, and maybe she could try and explain why exactly she did something like that so out of the blue.

However she was pulled out of her thoughts a moment later when her older brother called to her, "Hey Illya, are you okay?" Shirou asked looking down to his younger sister with a slightly concerned expression.

"Huh? Oh yeah, I'm fine Onii-chan,"

Illya replied with a smile as she came back to her senses, and looked back upto her elder brother, pushing all her thoughts about her sister to the back of her mind, while Shirou just smiled back down to her, glad to see that nothing was wrong with her. Illya just deciding to leave it for now and finish washing the dishes, maybe she could just go apologize and explain herself to Kuro later, giving her sister some space until then.

…...

Now after getting all of the dishes done, Illya sighed a little knowing that she would eventually have to apologize to Kuro, and she guessed now was as best time as any. Leaving the kitchen as she was soon making her way up the stairs and to her bedroom, guessing that that's where Kuro had gone to finish her homework since she knew that she had been told to stay out of the room she normally shared with their Mother, in order to keep it tidy.

Knocking on the door lightly, Illya stood waiting for a reply, which she soon got thankfully. "Come in," Kuro called from inside the room, causing Illya to give out a small sigh of relief, as it didn't sound like Kuro was mad or anything right now, and that meant that she may just be willing to talk as well.

Slowly opening the door Illya walked into the room with a slight smile, "Hey Kuro, I wanted to apologize for the way I acted earlier, I don't want came over me, I must have just…" Pausing Illya now stood not knowing what to say, or how to react frozen still as she saw Kuro on her bed in that cat-maid outfit again, but this time she was on all fours looking upto her with a curious expression.

Seeing that maid outfit again, along with those cute little twitching cat ears, and that smooth curled tail that lay on the bed swishing from side to side slowly. It was all getting to Illya too quickly, her vision too clouded by her own desires that she couldn't not look at her sister right now.

"Cute…"

Illya whispered out, feeling her heart already beginning to race, along with slight heat raising upto her cheeks, while she gazed to her sister and trembled all over, trying to hold herself back at best she could.

Kuro smirked as she looked to Illya's stunned expression, now knowing that it was how she looked in the cat-maid outfit that had made her act the way she had earlier, _'It's the same as before, so she really does have a thing for cute outfits, or maybe it's just cat-maids,'_ Kuro thought, before she moved closer to the edge of the bed, and sat with her legs dangling over the side looking to her shaking sister with a smile.

"What's wrong Illya? Did I flip your switch?"

She asked tilting her head to the side slightly, causing her ears to move along with her head, twitching slightly and flicking back against her head, while her tail slowly swished back and forth on the bed.

"I umm…"

Illya couldn't find the words to speak, as she didn't know what to watch, those cute little twitching ears, that long swishing tail, Kuro's alluring expression drawing her in, or…the little golden bell which was attached to a small red collar that Kuro was now wearing around her neck, the bell jingling slightly whenever her head moved.

' _That bell, nor the collar was there before… it makes her look even more like a cute kitten. Just what is Kuro trying to do right now…wait does she want me to do the things I did to her earlier…did she actually enjoy me doing those kind of things to her?'_ Illya questioned while she closed the door behind her, her mind now slowly going blank, as her desires were already getting the better of her, letting herself walk up to the bed, while her eyes now stayed locked on Kuro's seducing expression.

"Come on Illya, I look just like a cute kitten right, don't you want to pet me?"

Kuro asked tilting her head to the side again, causing her ears to twitch along with her, leaning forward as Illya swallowed slowly, she took a couple of steps towards her sister reaching her hand out, as she was slowly giving into her desires, but was still trying to fight them off at the same time.

Kuro just smiled as she felt Illya rest her hand on top of her head a few moments later, petting her head and scratching behind her little ears, before she moved her hand down to Kuro's cheek and stroked her under her chin lightly.

Kuro nuzzling into Illya's touch, while she made a soft purring sound and rubbed herself into her sister's gentle touch, acting like how a real kitten would, and waiting to see if Illya would continue or stop herself here.

"K-Kuro…"

Illya nervously just continued to stoke her sister's cheek, not knowing if she should really let herself go and fully give into her desires, or try and stop herself still before she did something that she would regret later.

' _Kuro what are you doing? Stop being so cute! Stop making me want to pin you down and kiss you again!'_ Illya pleaded inside her mind, feeling like she was so close to losing herself right now, and not feeling like she could hold herself back for much longer if Kuro continued to keep this act of her's up.

"It's okay Illya, right now I'll let you do whatever you want to me. So go right ahead and treat this cute kitty however you want," Kuro smiled winking to her sister, while she raised both of her hands up and made a cute pose with them, making them look like cats' paws, and stuck her tongue out in a playful manner, wondering just what it would take for Illya to break.

And apparently that line, plus with the pose added on top was enough it seemed, as Illya finally gave up trying to fight what her strong desires were begging her to do right now, and let herself play into Kuro's hands not being able to hold back any longer.

Illya allowed her desires to run wild, surprizing Kuro a moment later as she grabbed both of her hands and pushed her down onto the bed, pinning her down and kissing her deeply finally answering to what her body had been telling her to do since she walked into the room, and saw her sister dressed in that adorable outfit again.

Kuro's amber eyes going wide for a moment, as the sudden kiss along with Illya forcing her down onto the bed surprised her, however she soon recovered closing her eyes and melting into the kiss, letting Illya take the lead for once and wondering just how far she would take this if she actually allowed her to.

Squirming underneath Illya a little Kuro held onto her hands tightly, their fingers interlocking as Illya's eager tongue explored Kuro's mouth and starting to gently suckle on her sister's tongue, Kuro giving out small gasps and moans between deep kisses, while her breath came out in heavy pants, feeling Illya lightly biting on her bottom lip as saliva ran down their chins slowly now.

Their lips soon parting as Illya had to eventually break for air, although the moment she stopped and took one look at her sister, she wanted to continue. Gazing at her blushing face as Kuro panted heavily, her eyes filling up with tears once again, Illya's eyes widened as seeing Kuro like this reminded her of how she looked before, only this time she didn't look confused or worried and she didn't seem scared at all right now.

"Is a kiss all you wanted to do?"

Kuro asked getting her breath back now, as she looked to Illya with that same curious expression, knowing that she was only enticing her sister more, which is exactly what she was going for at the moment.

Illya just shook her head in reply, not being able to find the words for what she really wanted to say right now, her mind was already completely blank at this point, and she was way too far gone in letting her desires lead her, to try and pull herself back and snap out of her aggressive, yet gentle state that she was in now.

"Then continue, like I said, 'I'll let you do whatever you want to me right now', so you can ravish me as much as you like," Kuro smiled as she relaxed against Illya, looking up to her confidently, resting her head back onto the pillow, and patiently waiting for Illya to continue, finding that she was actually starting to like this unknown side to her sister.

Nodding slowly before swallowing loudly, Illya took a deep breath as she leaned down to Kuro again, kissing her lips lightly and then leaving a trail of light kisses down her jawline, and stopping at her neck. Sending shivers down Kuro's spine as she gave her exposed neck long and slow licks, gently sucking on her skin, but being careful to not be too rough, as she didn't want to leave a signal mark on her sister's perfect darkly toned skin, which was now starting to glisten with her own sweat.

Leaning her head back to give Illya more of an easy access, Kuro moaned slightly gripping tightly onto her sister's hands, as she could feel Illya licking and sucking on her skin continuing on down to her collar-bone, causing more shivers to run throughout Kuro's body as a fire now began to slowly build up deep inside her core.

Kissing oh so softly now, Illya slowly pulled away looking down to Kuro's chest, and feeling like tearing the fabric right off but at the same time not wanting to ruin the costume that Kuro looked so cute in. Kuro looked up to her sister, raising an eyebrow to her as she looked to where her gaze was stuck on right now.

"Do you want to touch them?" Kuro asked, as Illya looked back to her now, seeming slightly taken aback.

"C-can I?" Illya whispered out, her lips quivering a little as she felt Kuro letting go of her hands, but they stayed where they were, shaking as she was scared to move them in case Kuro suddenly backed out of this or something.

"Go ahead," Kuro simply answered as she thrusted out her chest towards Illya, her smirk now gone, and instead that cute, curious expression was back again.

Slowly moving her hands down Illya rested both of her them over Kuro's covered breasts, kneading them softly as she looked to see her sister's reaction. Kuro letting out a long sigh in return as she could feel her heart racing inside her chest, her breathing slowly turning into heavy pants while Illya continued to massage her small mounds, circling her fingertips around her hardening nubs, feeling them standing erect through her clothing.

Hearing Kuro begin to let out small moans, Illya wanted to see more of her cute reactions, and give her more pleasure, stopping her touching as she slowly moved her hands away from her sister's chest and looking to her with a wanting gaze.

"Kuro, I want to taste…your breasts,"

Illya spoke in a low voice her hands shaking again, as she really just wanted to dominate Kuro right now, and make her give out more of her adorable moans, but she knew she had to hold herself back, Kuro was letting her do this, but she probably wouldn't continue to do so if Illya scared her like she did before.

"Shall I take this off then?" Kuro asked gesturing to the maid outfit she was wearing.

"NO!"

Illya paused as she realized she had said that too loudly, surprising Kuro as her sister looked to her with a slightly frightened expression, obviously showing that she didn't like that forceful and demanding side of her.

' _Damn it, stop scaring her!'_ Illya cursed herself as she gritted her teeth, before she took a deep breath, calming herself as she looked down to Kuro again, "Don't take it off, I want you to keep it on," she stated quietly, feeling ashamed for not being able to keep herself in check.

"Okay, shall I just undo the top then?" Kuro asked seeming fine to Illya's relief now as that frightened expression left and was replaced with another cute and curious one.

Illya just nodded as she sighed a little, pulling away from Kuro as she let her sit up on the bed, Kuro simply reaching her hands round to her back, and unzipping the maid costume pulling the zip down to her waist slowly while Illya watched her. Those cute little, twitching ears catching her eyes again, as they flicked back onto Kuro's head as she pulled the top of her outfit down to rest around and still be covering her waist, her training bar being pulled down along with it.

"Kuro?"

"Hmm?"

"Can you feel anything through these ears?" Illya asked, continuing to watch her sister's cat ears twitch along wherever her head moved slightly.

"No, they're fake," Kuro simply answered as she now relaxed, leaning back and propping herself up on her elbows, while she looked back to Illya.

"Then how come they move along with your head?"

"I made them with my mana, so they still react to me moving around, but since they aren't really attached to my body, I can't feel a thing through them just like the tail," Kuro explained as she gestured to her tail, as it swished from side to side every time she moved her hips. Illya glancing down to Kuro's moving tail for a moment, before she looked back to her cat ears again, reaching upto them as she softly stroked them, taking the tip of one up to her lips and licking it lightly, hearing a gasp come from her sister in response.

But that was the only reaction she got, as Kuro looked up to her sister, surprised as she watched her lick and kiss her cat ears lightly, soaking them in her warm saliva, _'I can't feel anything through these ears…but seeing Illya doing such a thing to me…well I'd be lying if I said it wasn't turning me on right now,'_ she thought, a deep blush covering her cheeks, as she could feel a wet sensation beginning to dampen her underwear, while she still continued to watch her sister.

Taking the tip of one of Kuro's ears into her mouth, Illya sucked on it softly, a weird prickly feeling on her tongue from all the fur, but she didn't care as she waited for some sort of reaction to come from Kuro, but when none came she just sighed slightly.

' _So she really can't feel anything from me playing around with these, and yet they still move along with her body like they're actually her's. Her mana sure is impressive,'_ Illya thought, before she sucked on the ear a little harder, looking down to Kuro's expression while Kuro just looked back up to her with a curious gaze, her face blushing, but her body not reacting at all to what Illya was doing to her ears right now.

"Careful you don't get any hairs in your mouth," Kuro simply said as she watched Illya take her ear out of her mouth, and give it one last, long lick, before she pulled away slightly and cradled Kuro's head in one hand, looking down to her again.

"You really do like this costume, don't you Illya?"

Kuro asked with a slight smirk, nuzzling into Illya's touch, while Illya just brought her into another kiss, their lips soon parting as Illya moved down to gaze upon Kuro's now exposed chest, her hands already kneading those plumb mounds, as she leaned down a moment later to kiss her sister's bare skin lightly.

Kuro trembling slightly as she felt Illya's hot tongue circling around her hardened nipple, taking the small nub into her mouth a moment later as she sucked on it lightly, while pinching the other one, causing Kuro to moan a little louder now.

' _Her breasts are so soft…just like her lips,'_ Illya thought as she closed her eyes and licked Kuro's stiff nipple slowly, coating it in her warm saliva, while she listened intently to her sister's slight moans of pleasure, wanting to hear more from her but knowing that going slow was the key right now.

"Ahh…Illya…mmm…"

Letting out quiet moans, Kuro was making sure to keep her voice down as best as she could, feeling Illya pinching and sucking on her nipples, then softly going back to kneading and lightly licking them, as she was quite impressed at how much Illya knew when she was in this state. Illya could tell that Kuro's nipples, as well as her breasts were sensitive, and so she was using that to her advantage it seemed, playing around with them as much as she could to hear more of Kuro's cute moans.

Kuro not being aware of it at first, but Illya had now began to move her hand down, leaving one of Kuro's breasts alone, as she slowly ran her hand down Kuro's clothed body and stopped when she came to her waist, playing with the end of her skirt a little as she heard Kuro give out a small gasp. However she didn't recoil, or protest as Illya slipped her hand under her skirt and began to gently caress her sister's covered privates, stirring her up through her panties tenderly.

' _She's going all the way? I'm impressed, I never thought she'd ever go this far with me,'_ Kuro thought as she looked to Illya, grabbing hold of the bedsheets, clenching them tightly in her fist as she knew that there was now no stopping Illya when she was this far gone in losing herself, but then it's not like Kuro wanted her to stop, after all her body was now starting to beg her for a release.

"W-wait…Illya s-stop…"

Kuro whispered out, speaking between heavy pants and low moans, as she looked to Illya with a pleading expression, causing her to look back to her with concerned gaze, halting her advances as she thought Kuro might not want to her go all the way with her, and may just ask to stop here or something.

"If you're going to touch me there, do it directly and take off my panties, I don't want them getting ruined," Kuro simply said blushing as she bit her lip and looked upto Illya, wanting her to remove her underwear quickly so that the nagging feeling of wanting a release wouldn't bother her for much longer.

"O-okay,"

Illya answered as she was a little surprised over what Kuro had just told her to do, but soon recovered, swallowing slowly as she leaned down to Kuro and kissed her deeply, Kuro melting into the kiss while she could feel Illya slipping off her damp underwear, throwing it to the floor a moment later.

Their lips parting as Illya looked to Kuro, seeing her blushing expression looking right back at her, before she slowly started to move her hand, gently stroking Kuro's dripping slit as she leaned back down and began to suck on her hardened nub again, her fingers thoroughly coating themselves in her sister's arousal, as she played with her clit a little and encouraged it to show itself to her eager fingers.

"Ahh…Illya…ahh!"

Kuro cried out a little as she felt Illya being gentle, but also going a little fast as it wasn't all that long before she slipped two fingers inside her sister's now soaking entrance, and starting to slowly thrust them inside, seeming to somehow know where pretty much all of Kuro's weak spots were.

"You're already so wet Kuro,"

Illya whispered as she gave Kuro's nipple a long lick, before she increased her speed a little, and grabbed hold of Kuro's tail with her free hand, teasing the furry appendage, while the end of it curled around her fingers, knowing that Kuro couldn't feel anything through it but at the same time not minding that fact, as she stroked the smooth fur.

Before looking back to Kuro's expression, and seeing her panting heavily as low moans escaped her lips, and her eyes were filled with tears, knowing that she was feeling pleasure because she was thrusting her fingers inside her, and not because of the fact that she was playing with her tail, but even so she liked to think that Kuro was maybe at least feeling some sort of pleasant sensation through her tail , _'Kuro really would make a cute kitten,'_ Illya thought as she closed her eyes and went back to sucking on Kuro's nipple lightly, while thrusting her fingers inside her deeply.

' _How is she so good at this? And how does she know where my weak spots are? If she keeps this up for much longer…I'm going to…,'_ Kuro thought, her mind now quickly going blank, as her heart raced inside her chest, and her amber eyes shut tight, feeling a heavy pressure now building up inside her lower abdomen, knowing that it wouldn't be long before she reached her limit.

"You're tightening around my fingers, does this feel good Kuro?" Illya asked as she could soon feel Kuro's walls clamping down on her fingers while her juices were overflowing and starting to soak into the bedsheets.

Kuro could only nod in reply as she reached one arm up and grabbed hold of Illya's shirt, gripping onto it tightly as she could feel Illya doubling her efforts now, causing her pleasure to almost instantly hit its peak. Kuro letting out a slight cry as she held her voice back, and could feel her climax now quickly approaching her.

"Illya…ahhh…I'm cumming….AHHH!"

Kuro let a cry out before she bit down on her bottom lip, and held back her screams of release, her waist raising up off the bed as she rolled her hips into Illya's thrusts, Illya making her ride out her orgasm, as she lifted her head a little and looked to Kuro's expression. Watching her moan through her climax, halting her fingers now but still keeping them inside her sister, while Kuro now panted heavily, recovering slowly while trembling all over, loosening her tight grip on Illya's shirt, and starting to now come down from her high.

However she didn't get much more time to get her breath back to normal, or try and calm her still racing heart down, as a moment later Kuro could feel Illya moving her fingers inside of her again, starting to stir her up quickly, and going for all her weak spots straight away.

"W-wait Illya, I just came so…so if you do that so suddenly…I'll…AHHH!" Kuro cried out as she felt another climax building up and approaching her fast, this one feeling much more intense than her previous one.

Illya simply just watched Kuro's expression again as she circled her tongue around her nipple, and kissed her soft skin lightly, thrusting her fingers deeply into her sister as she wanted to make her cum quicker this time. Already doubling her efforts, seeming to know exactly what to do in order to make Kuro reach her limit.

Kuro not being able to hold back at all, as she quickly covered her mouth with one hand, muffling her screams of sheer pleasure, while she threw her head back in absolute ecstasy, now becoming overwhelmed as her tears of bliss leaked over her eyelids, and ran down her cheeks, her whole body convulsed as her second orgasm rippling through her.

Illya not letting her rest for a single second as wave after wave of unimaginable pleasure washed over her again and again, riding out her climax until she felt Illya finally remove her fingers from inside of her, and she collapsed on the bed.

Now panting heavily, trying desperately to get air back into her lungs, Kuro draped an arm over her eyes, her body still shaking and twitching while Illya now sat up straight, pulling away from her panting sister as she reached her drenched fingers upto her lips, and licked them clean of Kuro's juices, savouring the sweet taste.

"No more Illya…no more…"

Kuro panted out as she looked back up to Illya now, moving her arm to lay beside her, as she still held tightly onto Illya's shirt, only noticing now that her sister was holding onto her tail and stroking it gently, smiling slightly as she really was surprised by how much this weird fetish of Illya's made her act so out of character.

"You look so cute when you cum Kuro,"

Illya whispered as she leaned down and kissed Kuro's forehead lightly, Kuro closing her eyes as she sighed deeply, feeling her breathing going back to normal now, and finally being able to now relax in her afterglow.

"So have you had enough now?"

Kuro asked wondering just how long it would take for Illya to go back to her normal self, or maybe she would have to find some way to snap her out of it like she had done earlier if she wasn't going to stop from here.

"No, it's not nearly enough,"

Illya stated, shaking her head in reply as she kissed Kuro's cheek, licking up her tears and grabbing hold of her hand, holding onto it tightly, wanting to hear more of Kuro's cute moaning voice and wanting to see more of her pleasure-filled expressions.

"You want to do it again? Okay maybe flipping your switch, and allowing you to do whatever you want to me wasn't such a good idea after all," Kuro thought out loud with a heavy sigh, seeing now that maybe Illya letting this side of her show was dangerous, especially since she didn't seem to get snapped out of it very easily this time.

"Kuro, where's Ruby?"

Illya now asked, stopping to look around the room, only noticing now that her wand was missing from where it normally lay on her bedside table. Seeming calmer now that she had made Kuro cum twice, but it was easy to see that she still wanted more, and still wasn't quite herself just yet.

"I told her to go round to Miyu's to see Sapphire, since I knew she'd be a pain if I let her stay while I tried this out on you, although maybe she would've helped in getting you to come back to your senses, since I don't see me having much luck here by myself," Kuro explained, her voice going a little lower as she seemed to be just mumbling to herself now as she looked away from Illya.

Illya looked worried now as she looked down to her and Kuro's hands for a moment and squeezed her sister's hand tightly, "I scared you earlier, didn't I Kuro?" she asked, a little worried for what Kuro's answer would be, as she still wanted to continue, but knew that she would have to back off if Kuro wanted her to, after all she really didn't want to see her frighten expression again.

"Huh? Oh no, you just surprised me that's all. I guess I didn't know just how aggressive you could get when I encouraged you to just let loose on me," Kuro answered simply as she now looked back to Illya, still seeming tired, but didn't look too bothered by the fact that Illya was still in the mood and wanted to carry on.

"Neither did I," Illya stated after a short pause, a little surprised by Kuro's answer, as she now lifted her head up and looked back to her, wondering what she would say next.

Kuro sighed deeply, thinking for a minute, before she caught Illya's attention again, "Listen I'll let you pleasure me, and make me cum as much as you want to, as long as I get to have my way with you as well. Deal?" she suggested looking to Illya with a slight smile as she didn't mind continuing, but she would like to send Illya into a mess of moans and panting like she had done to her.

Illya's eyes widened as she didn't believe what she had heard at first, going over what Kuro had said in her mind a few times, before her lips formed into a smile,

"Deal!" she nodded happily, feeling more than overjoyed at the fact that Kuro was going to let her continue with pleasuring her to her hearts content.

Getting a smile back from Kuro, before she thought for a moment and looked a little troubled now, "But Kuro, is it really okay for us to do this, we are sisters after all?" she asked, wondering if when she was back to being herself again, she would possibly regret doing all this with Kuro.

"Well it's a little late for us to question that now don't you think? Don't tell me you want to stop here?" Kuro asked, tilting her head to the side, that cute curious expression back on her face again now.

"NO!"

Illya shook her head frantically, realizing that she had said that a little too loudly, expecting Kuro to have that scared look on her face again, but when she looked all she saw was Kuro simply smiling to her.

"Neither do I,"

Kuro whispered, her voice having a seductive tone to it now, as she sat up and rested her forehead against Illya's interlocking their fingers and kissing her lips lightly a moment later, before she pulled away a little and pulled Illya to be leaning over her again.

"And if it does feel weird to you, we can just think of this as another mana transfer, okay?" Kuro smiled as she wrapped her free arm around Illya's neck and held her close, feeling her stroke her cheek a moment later, as she nuzzled into her touch more.

"Okay,"

Illya nodded, her lips forming into another smile, as she knew even if she did come to regret doing this when she woke up in the morning, at least she hadn't hurt Kuro in the process, and if they never did this again they would at least have this night to remember.

However Kuro knew that this would no way be the only time they would do something like this, after all she knew how to flip Illya's switch now, and was looking forward to uncovering more about this assuming side to her sister.

Kuro smiling to herself as she brought Illya into another deep kiss, the two of them soon continuing to make love late into the night, finally ending with the both of them falling asleep in each other's arms once they had well and truly exhausted themselves, cuddling close together while content smiles formed on their lips, and their hands tightly held onto one another lovingly.


End file.
